concepts

Concepts are mental representations that categorize objects, events, or ideas according to shared properties or relations. They enable thinking, communication, and planning by allowing inferences about unknown instances and guiding behavior when confronted with new situations. In philosophy, a concept is often treated as the content of a mental representation that is used to think about categories, properties, and relations, and which may be analyzed in terms of its intension (the set of properties that define it) and extension (the set of things it applies to). In cognitive science, concepts are studied as the building blocks of knowledge, formed through perception, language, and social learning, and organized into hierarchies such as basic, subordinate, and superordinate levels.

Representations of concepts take several forms. Feature-based accounts describe concepts as lists of distinguishing properties. Prototype theory posits that some category members are more representative than others, forming a central tendency or prototype. Exemplar theory proposes that categorization relies on memories of specific instances. Schemas and scripts capture relational and procedural knowledge about typical situations. Some concepts are defined by necessary and sufficient features, while others are organized by similarity, family resemblance, or contextual cues.

Concepts develop through experience and language, with variation across cultures and individuals. Children acquire basic concepts early and progressively build more complex ones, using social input and education. Concepts also interact with categories and classification systems in science, mathematics, language, and everyday reasoning.